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DAx Data Acquisition and Data Analysis

Size Exclusion Chromatography / Gel Permeation Chromatography support in DAx

  DAx has all the features that are needed for chromatographic applications in general, such as the ability to measure sequences of measurements, recognise and quantify components, and compare measurements.
It also contains a number of features geared specifically towards Size Exclusion Chromatography / Gel Permeation Chromatography:

New application note:

Comparison of GPC analysis using DAx and using spreadsheets (263 kByte / 12 pages)
This application note also serves as a manual on the interpretation of molecular weight distribution data in text files.

Calibration Curves relating Molecular Weight to Elution Volume
Calibration curves can be multi-linear, cubic spline, or polynomial (up to 10th order). Curves can be plotted linearly or logarithmically.

Peak lists can display one or all of
  • Mp (mol weight at peak top)
  • Mn (number averaged mol weight)
  • Mw (weight averaged mol weight)
  • Mz
  • D (dispersivity)
  • Mol weight at peak start / Mol weight at peak end
Mw Axes
Traditionally, chromatographic measurements have a horizontal axis depicting time coordinates. Using an Mw calibration, DAx can convert measurements to have a horizontal axis depicting molecular weight or log(Mw).

Converting between concentration and weight data
Chromatographic measurements typically measure component concentration or component weight. The distinction is important when calculating peak parameters and when drawing molecular weight distributions.

Identifying components by molecular weight
Components can be identified by Mp, Mn, Mw or Mz.

Molecular weight axes
Data can be plotted with a molecular weight axis instead of a time axis. If baselines are present, they can be automatically subtracted from the data to give a much cleaner plot. The plots can be normalised so that the accumulative molecular weight in all peaks that are present is 100%, making it very easy to compare molecular weight distributions between different measurements.

Mouse tracking
When the mouse cursor is tracked over a graph, the molecular weight at the cursor's coordinate is displayed.